Rotary rock-drill bit



R. o. wcm. ROTARY HCi D F'ILL B5?.

APPLlCATlON HLED IUNE 15, i911.

Patented Mar. 23, 1920.

UNITED sTATEs PATENT oEEIoE.

ROWLAND 0. PICKIN, l SEATTLE, WASHING-TGN.

noranr. noon-:DRILL nir.4

naar,

tpeciiicaton of Letters Patent.

Patented lllan. 231, i920.,

.application tiled lune l5, lul?. lSerial No. l'lltft.

dh all whom it may concern:

Be it lrnown that ll, Ron/Lann U. Pronrn, a. subject of the lling of Great Britain, residing in deattle, in the county of lling and hitateof Washington, have invented a new` and drill rod. A

il; principal object ofthe invention is the provision of certain improvements more particularly hereinafter described and designed to increasethe efficiency and `economy of operation of such a tool.

. rllhis invention contemplates the provision of a rotary detachable equalizing bearing for holding the tool or cutter in the drill head and designed to insure an even distri- Btl bution of the pressure on the cutter, and, at the saine time, materially reducing the incidental friction.

il still further object of the invention is the provision of an improved system of lubrication together with the appropriate de- -vices for improving the general operation and adapted to prevent the entrance of grit or mud-laden water or duid Ibetween the relativelymoving surfaces.

l still further object'of the invention is the provision `of a lubricating system whichv l will economize in the consumption of lubricant by preventing escape of the lubricant during the drill operations.

Still .another object of the invention is the provision of a drill in which the parts may be readily removed for repairing or replace ment when said parts become worn or damaged in use.

Other objects and advantages of the invention will be apparent as it is better understood from the following description when considered in connection with the accom- Apanying drawing illustrating' a preferred embodiment thereof.

On vthe drawings, p' A c Figure 1 is a vertical sectional view taken on the airis of the cutter and hole or boring of an embodiment of my present invention;

lFig. 2 is a hottom plan view of the cutter showing a preferred arrangement ofthe teeth; and

yllig. 3 is a vertical sectional view similaito lig. l showing a slightly modified form.

llt will be understood that a drill constructed in accordance with my invention comprises a drill member carrying the operative parts and secured in the end of a vertically disposed rod or shaft, which, since this general arrangement is well lrnown to those slrilled in the art, is not shown on the drawing. rlhe member in the ypresent instance comprises a threaded shank ll adapted to he secured into the end of a shaft or otherwise coupled thereto and extending up from a hollow casing head l2. rlfhis head is provided with an interior cavity 13 closed at` its bottom with a plug or bearing head proper lt carrying a cutter l5. The lower face le of the plug 14- is inclined at an appropriate incline and is provided with a perforation or opening l? through which a shank lil of the cutter eirtends. rll`he cutter in the present instance is provided with a pair of flat cutting faces i9 and 2l, being1 locatedsulostantially at the intersection of the aires o-f the cutter and of the casing l2, this intersection of the axes providing the center of gyration and the general construction arranging the center of gyration in the lowermost cutting face.

The cutter is preferably of one piece and isI formed to provide a shank 22 extending through the opening or perforation l? in which said shanlr or shaft has a bearing for independent rotation. 'lhe body of the cutter7 e., that part above the cutting face 2l has a rear flat surface providing a hearing face 23 adapted to engage the under inclined faceE 16 of the plug lt and the upper end of the cutter shank is threaded at 2t to receive a holding nut' 25 and lock tap screw 26 for holding the cutter in place and against excessive longitudinal movement. Packing is provided between the nut 25 and the plug and also between the head of the cutter, and between the faces i6 and 23. Considering first the packing between the nut 25 andthe upper face 27 of the plug,

it will be noted that a washer 28 is disposed aloout the shank 18 and upon this are located yielding packing rings 29 adapted to prevent the passage of Water and lubrt through the cutter and out around the outa side of the teeth, as will be later described.

A lubricating device is located withln the c hollow head 12. In the form of the invention shown in Fig. 1 this lubricating device comprises a rigid container 32 carried upon a stem 33 screwed into the open portion of the plug 14 at 34. This lubricating dev1ce is open at its top and it is intended to contain a more or less solid or semi-solid grease. This grease is preferably confined within a canvas or other flexible covering 35. A hollow plug 36 is providedthrough the bottom of the canvas or yielding container and screws into the stem 33. The stem 33 1s provided with a longitudinally extendmg l passageway 37 communicating with the hollow interior of the plug 36.. A set screw 38 is provided through the side of the stem 33 to control the passage of lubricant. The

canvas or other yielding covering carries a weight adapted to bear down upon the 'grease and the vibration of the said weight forces the grease downthrough the stem as it may be required for use. This weight in the present instance comprises a heavy bolt 39 screwed into a sleeve or collar 41 having afflange 42 located within the flexible covering of the grease, a collar 43 being provided to screw down against the fiange and hold the weight in place with respect to the material of the cover.

A` cavity 44 is located beneath the end of thev stem 33 and the grease passing through the stem moves into this cavity and from the cavity through a passageway 45 passes into the perforation or opening 17. Here it is confined by the packing earlier described and it is intended that the entire available space within this opening be filled with the lubricant, the -packing preventing the lubricant from exuding out either at the to or bottom.

cutter, being admitted to the cavity of the hollow head 12 through apassageway 46 plug 14 to equalizethe thrust ofthe pressure, Iesulting from the operation of the tool.

The lower portion of the perforation or opening 17 is enlarged and given a spherical curvature, as indicatedat 49 in Fig. 1, and in this enlargement is inserted a thrust ring 51 having an under face 52 curved to engage ow of water is maintained in the bearing balls 53 positioned between the face 23 of the cutter and the lower curved face of the bearing ring 51 and the adjoining faces of the bearing ring and plug so that a proper fit is readily obtained. The side thrust of the balls is taken up b a second thrust ring 54, mounted also within the plu 14. The curved contacting faces 49 permlt the bearing ring to adjust itself and distribute the thrust evenly as will be later more fully explained. An enlargement 55 of the opening 17 is'also made at the top and in this enlargement are located bearing balls 56 which engage a thrust ring 57 comprising through thecutter itself. In this form of the invention the water is kept from contact with the upper end of the shank of the cutter. The cutter indicated at 64 has the shape and general characteristics of the cutter 15 and is similarly mounted through the plug 62, itsshaftv or shank 65 extend,- ing through an opening 66 in the plug. A housing 67 excludes the water from contact with the upperl end of the shank which is held in placeJ by a nut 68 in the manner already described. The housing 67 carries ya' rigid lubricant container 69 having a cap 71 at its top. The grease vwithin the container 69 Vis also provided with a covering of canvas or other flexible covering 72, which in the present instance however does not infold the lubricant, consisting merely of a sheet secured at its edge 73 between a flange 74 of the container and the lower end of the threaded neck 75 of the cap. A weight 76 is carried by this covering, and in the present instance, this weight consists of a bolt lhaving a head 77 within the covering and a collar 78 secured down thereagainst to hold the material of the covering to the weight. vThe body of the weight consists of the stem which extends up through an opening 79 in the cap. If desired, a spring 81 may be positioned beneath the cap and in engagement with the cap and withV the collar 78, tending thereby to force they covering down to compress the oil or lubricant against the bearing. The container 69 is' provided with' a lhollow threaded stem 82 extending up through the top of the housing 67 so that the action of the weight and spring is to keep the housing full of lubricant. A lubricating passageway 83 passes down into the stem and branch passageways 84 and 85 take off at appropriate locations.

Packing rings 86 and 87 are provided similar to packing rings 29 and 31 and similari)7 located. 1

'lhe internal shape of the opening 66 is identical with the opening 17 and the parts about to be described and mounted therein may be 'considered to be interchangeable with the similar or analogous parts already described and located in the opening 1l', slide rings, however, being used in place of the bearing balls.` 'lhese slide rings each consist of avpair of rings 88 and 89, the lower one 88 being arranged to fit close about the shanlr against the rear face of the cutter and the upper one being adapted to rest thereupon and beneath a thrust ring 91 of shape substantially that of the thrust ring 5l, except that the lower face is dat instead of curved. lllach ring is provided with an encircling lubricating groove 92 and with cross-grooves 93 indicated in dotted lines and communicating with the passageway 85 from the passageway 83 in the shanlr of the critter. lf desired, lreys 9d can be provided for preventing independent rotation of the thrust ring with respect to the plug and independent rotation of the slide rings with respect to the thrust ring and cutter respectively. il ring 95 is positioned in the enlargement 96, which is identical with the enlargement 55 of the earlierv described embodiment. *'llhe ring 95 is provided with a channel in which is positioned paclring or other lubricant absorbent material communicating with the passageways 8d. rllhe contacting faces 98 between the thrust ring 91 and the plug 62, and the analogous contacting faces in the earlier embodiment, are curved to spherical form so that these faces may move over each other to equalize the thrust as the parts may Wear slightly, and, this, of course, whether the ball bearing arrangement shown in Fig. 1 or the slide bearing arrangement shown in llig. 3 be used.

The invention also contemplates an irn-A proved arrangement of the teeth of the cutterq which is shown in Fig. 2, from which it will be noted that on the lower face 19, the teeth are formed of serrated ribs 101 extending parallelly `with each other across the entire face and the face 21 is provided with a plurality of ribs 102 arranged radially and a plurality of ribs 103 arranged in parallelism. lt will be noted by comparing lligs. 1. and 2 that the cutter has a roller action over a surface of greater diameter than the cutter itself and this diversified arrangement of the teeth causes an everchanging presentation to the surface being operated upon. The action is a crushing one "as counter-distinguished from a scraping one, and this arrangement of the teeth prevents the formation of a ribbed surface beneath the cutter corresponding in some degree to the hills and valleys provided by the ribs. The ribs 101 are serrated at intervals to set-off individual teeth. These serrations entend spirally as indicated in the the form hereinbefore described being merely a preferred embodiment thereof.

l claim:

1. lln a roch drill, the combination of a head, a cutter mounted for independent rotation in said head and having a shanlr extending therethrough, bearing devices between said cutter and said head, and a thrust equalizer for transmitting the thrust of said cutter through said head.

9. ln a roclr drill, the 'combination of a head, a cutter mounted for independent rotation and having a shank extending into said head, and a spherical bearing about said shanlr for equaliaing pressure of said cutter transmitted to said head.

3. ln a roel( drill, the combination of a head, a cutter mounted for independent rotation, a stem connection between said cutter and head, and an equalizer embracing said stem and equaliaing the pressure transmitted by said cutter to said head.

d. ln a rock drill, the combination of a head, a cutter mounted for independent rotation and having a stem extending through an opening in said head, and an equalizer engaging said head, the contacting faces of said equalizer and said head being spherical to equalize the thrust of said cutter on said head.

5. ln a roclr drill, the combination of a head, a cutter having a stem extending through said head and independently rotatable thereon, means for supplying lubricant within said head and about said stem, and means for excluding water and grit from about said stem within said head.

6. ln a rock drill, the combination of a head, a cutter having a stern disposed through said head, a nut engaging said stem beyond the head, and a yielding packing located between said nut and said head and the body of said cutter and said head,

7. A cutter for a rock drill comprising a cutting face having a plurality of radially extending teeth and a plurality of parallelly extending' teeth arranged in a plurality of parallel planes.

, 8.. A cutter for a roolc drill comprising .two tiers of cutting faces having a combination of teethA arranged radially, spirally and parallelly with respect to each other.

r9. In a rock drlll, the combination of a 5 head, a cutter mounted for independent rotation in the head, and a thrust equalizer for transmittingequally the thrust to said cutter through said head.

10. In a rock drill, the combination of a 10` head, a cutter mounted for independent rotation therein, and a spherical equalizer for equalizin pressure of said` cutter transmitted to sai head.

Signed in the presence of two subscribing witnesses.

RDWLAND O. PIGKIN.

Witnesses:

- Mrs-JESSE M; LIGH'rFooT,

V. A. MONTGOMERY. 

